Lock for locking manhole and vault covers



July 4, 1944.

1.. H. wrr'r 2,352,750

LOOK FOR LOOKING MANHOLES AND VAULT COVERS Filed May 14, 1942 2 Sheets-Shee t l WWWHHHIHHIH July 4, 1944. Q wrr'r ,mcx on LOCKING 'MANHOLES AND VAULT COVERS 2 Sheets-Sheet 2 Filed May 14, 1942 :1 IIIIIIIIIIIIIIIIIL INVENTOR.

. M y/M414 (EM-7264M Patented July 4, 1944 UNITED STATES PATEINTIFOFFICE LOCK FOR LOCKING MANHOLE AND VAULT C'UV'ERS Irwin H. Witt, Blue Island, Ill. Application May 14, 1942, Serial No. 442,982

4 Claims. (Cl. 7.0168) This invention relates generally to locking means, and more specifically to locking means particularly applicable to manhole covers and vault covers and the like. Such application of my lock is not tobe considered limiting for it is applicable in conjunction with a variety of closure elements in many other locations and for other purposes.

It is an object of my invention to provide a closure element, such as a manhole or vault cover, with which a locking means is associated having a sliding bolt, and a screw means associated with the closure element and locking means, the screw means and the bolt being formed to provide for opening and closing of the bolt of the locking means in certain predetermined positions of the screw means with respect to the bolt. Further, in the preferred form of my invention the closure element comprises a plate member provided with openings for the reception of the screw means so that the latter may be positioned to lie within the exterior of the surface of the plate member in the locked position of the bolt thus affording a smooth level external surface. Alternatively, if desired, a pivoted catch may be suitably secured to the inside of the cover and positioned to cooperate with the bolt of the locking means for securing the closure element in closed position.

Figure 1 is a plan view of the lock itself;

Figure 2 is a front elevation of the lock of Figure 1;

Figure 3 represents a side elevation of one of the two or more lock screws in which may be seen a slot in the shank of the screw and the truncated edge of the cap;

Figure 4 is a plan view of the bolt of the lock showing at its left hand end the two threaded portions and near the middle the operating lug which is preferably set into a notch therein;

Figure 5 is a vertical cross section on the line 5-5 of Figure 6 showing how the lock is fastened to a cover plate and how the plate is locked in place;

Figure 6 is a plan view of the cover and lock of Figure 5;

Figure'l is a vertical cross-section taken along the line 'l'| of Figure 8 and showing another manner of locking the'cover plate in place; and

Figure 8 is a plan view of the cover and lockin means of Figure '7.

Referring now to Figure 1, the reference numeral l0 indicates generally the lock'itself. The twoouter plates II and I2 respectively have the same dimensions and are spaced apart by two the lock bolted thereto by screws.

spacers or side plates 43 and H which are preferably welded to one or both of the plates II and 42 as may be seen in Figures 1 and 2, the spacer 'l 3 running the full length of th lockwhile I the spacer I4 runs approximately two-fifths of the length of the lock on the opposite side. Between these spacers l3 and I4 is thereby formed a passageway in which lies the bolt l6 which is flat andwide and has a substantially rectangular cross section. The'bolt I6 has an operating lug or handle H which is formed of a rectangular piece of the same'thickness which is inserted into a recess in the side of the bolt I6 and is welded thereto. Obviously this boltand lug could be forged or otherwise formed integrally. The separately formed lug I! may be made of a toughergrade of steel than the bolt I6, and hence presents an advantage for the specific constructionshown'.

As.1may be seen in Figure 1, this lug or handle 11 protrudes from between the plates H and I2 because plates H and I! have registering recesses formed in their sides to expose-the lug H. The handle or lug I1 has a slot or notch I8 into which a rod or pointed implement may be inserted and used. to push the bolt backward and forward when the bolt is released. At each of the four corners of the lock, holes l9a, I911, and 19d are drilled all the way through so that screws may be inserted therethrough from the underneath .side and led into the bottom of a cover plate which is appropriately drilled and tapped for said screws. If the .cover plate is thin, then nuts may be welded to the under side and This means that screws or bolts need pass through the cover plate in order to fasten the lock thereto. A spacer ring 20 or block is placed at the lower right corner of the look as viewed in Figure 1 in direct alignment with the hole I90 passing through that portion of the plates H and i2 of the lock. This spacer is removable when the screw which passes therethrough is removed. Complete withdrawal of the bolt from its housing is then possible. Ihe ring serves not only to space apart the plates II and I2 from each other, but'also serves to guide the bolt Hi and to limit its field of motion. The motion of the bolt in a longitudinal directionis limited because the lug I1 is limited in its movement to the right (as viewed in Figure 1) by spacer ring 20, and is limited in its movement to the left (as viewed in Figure 1) by the spacer block 14. The two lock screws'22 and 24. pass through both of the plates H and and through the sides of bolt [6 as will be described more fully hereinafter. Though the use of two such screws is here illustrated, it is permissible to use a single screw or a plurality of screws. At their ends these screws each have nuts 2|, 2| and 23, 23, respectively, welded together. This prevents removal and loss of the screws.

Referring to Figure 3, screw 24 will be seen to have a head 25, which head has a flange 26. On the shank of the screw 24Ithere is a square'notch transversely cutout portion 21. a similar notch or portion cut out of the shank,

Screw 22 has but this cut out portion is closer to its head than" ure 3, which is substantially exactly equal to p the thickness of the bolt Hi. The head of each screw is cylindrical except that it has one side i truncated or slabbed off. This is done so that the head presents an engaging surface whichcannot be eifectively engaged so as to turn the screw except with a special tool having a corresponding socket, in other words, a special socket wrench. This provides an additional meansfor preventing tampering with the lock.

When the plates- II and I2 and the spacing elements l3 and I4 have been welded together in proper relation, the boltlB is inserted therein and positioned as is indicatedin Figuresl and 2; that is, the right hand end-'of thebolt l6 protrudes from between the plates II and I2. This is the position the bolt will assume when it is to be used for locking the closure elementa manhole cover or a cover plate-to its seat. A jig is then mounted on the plate II, and the plate H, bolt l6, and plate I2 are then drilled and tapped. A jig is particularly desirable for tapping because it permits the threads of the tapped holes to begin at the same position for every lock mechanism. The importance of beginning the thread at the same position for each lock will be noted more clearly hereinafter when the com bination of the lock is explained. Tapping the plates II and I2 and the bolt Iii-results incomplete threaded holes through the two plates, but only segments of a threaded'hole through the bolt, as may be seen more clearly in Figure 4 at 33, 30.

After the tapping operation, the lock screws 22 and 24 respectively, are threaded through the plates and bolt. Aspreviously mentioned, the screws 22 and 24 have. a .cut out portion 21,21 intheir shanks as is illustrated in Figure 3; Though the length of theshank of each of these screws may be thesame, the location of the'cutout portions 21 and 21' varies in order to produce a combination for the lock which is difiicult to solve. The combination may be different for every lock; Pairs ofz-lock nuts are then threaded onto the lower ends of the screws 22. and 24 and welded together and to the screw so that they may not be removed. By virtue ,of theselock nuts 2|, 2| and 23, 23, respectively, and the flanges 2'6, 26 of each screw, it is impossible to remove the screws from the plate and bolt. They may merely be threaded up and down between these limiting elements. Thethre'ads of the screws 22 and 24 engage the corresponding grooves 29, 29 in the arcuate notches 30, 30 of the bolt [6. This prevents the bolt from being moved in its passageway in the housing formed by the plates H and I2 and the spacing elements l3 and I4. In order tounlock thislocking mechanism it is necessary to thread the screws 22 and 24,respect v into u h ar s io withn es ec tq th bolt l5 that the notches or cut out portions 21, 21' of the screws register with the way formed by the housing. In other words, the notches must register in both axial position and angular position with the outline of the bolt 16 before the bolt can pass through the notches 21 and 21. Figure 2 illustrates the screws in this position, and it will be noted that one projects further above the surface of plate II than the other. This is due to the fact that the cut out portions 21, 21 of the screws are spaced at different points along the shanks of their respective screws. Threading these two screws into the position shown in Figure 2 amounts to unlocking the locking mechanism for, at that time, the bolt It may be slid freely back and forth through the passageway between the plates H and I2. Though the arcuate notches 30 are shown to be v threaded, this is not essential since the screws 22 and 24 would still lock the bolt by projecting into the notches in its edges. The threads, however, help prevent persons attempting to pick the lock from feeling the combination if it is accidentally reached,

When it is desired to move the bolt It to cause it to look a cover plate to which said lock. is affixed with respect to its seat, a rod or pointed instrument is inserted in the slot or notch I8 of the lug or handle I! of said bolt, and the bolt is urged to the right as viewed in Figure 2 until said lug or handle I! abuts against the spacing ring 20. In this position the threaded arcuate notches of the bolt l6 are in direct-alignment with the tapped holes in the plates II and I2. This alignment permits the screws 22 and 24 to be threaded either upwardly or downwardly, either of which actions will cause the threads of said screws to engage the grooves of the bolt 5. The bolt cannot then be moved in any direction.

Lubrication of this lock consists of a very occasional shot of oil and graphite in the passageway of the housing and in the holes for the screws 22 and 24.

In operati0n, the screws are always threaded down toward th plate ll so that no projection will be presented on the surface of the manhole cover or other covering plate to which the lock is affixed. These screws are threaded down tightly against plate II as may be seen most clearly in Figure 5. The cover plate 33, to which the lock I0 is affixed by screws 34, 34, has three holes through it. Two of these holes, the key holes 35, 35, accommodate the screws 22iand24. A slot 39 is formed in the cover plate to provide access for a suitable tool for insertion int o lthei notch l8 of the lug I! for shifting theboltlfi When screws 22 and 24 are threadedtightly, against the plate H of the lock I0, the heads of, said screws lie below the upper surface -of {the cover plate 33, and the flanges 26,-26 of .said heads 25, 25 substantially fill the; holes 35,3310. prevent dirt getting between theflangesZG, 26 and plate I I of the lock l0. A single slot ofsiifli cient width could be substituted for the'i'ndi vidual key holes. I

In conjunction with Figures 5 andfi/Ishall now describe how the lock mechanism-l0 is unlocked. As may be seenfrom these. two figures, the cover plate 33 is locked onto the seat. 31 by means of a hook 40 afiixed to; oneledg efof the cover plate 33, which hook .eng'ag'es'JtheIunder side of therim 38 of the seatI31, a'ndibyv the bolt "5- of the lock mechanism l0, which'boltf'n'gages the under surface of the rim' 3;; ofithe sear at the opposite side. The screws 22 and 24 have been threaded downwardly so that their heads 25, 25 and flanges 25, 26 press-tightly against the plate ll of the lock Hi. The operator who will open the lock knows the combination, which combination consists of the knowledge of how many turns the screws 22 and 24 must be threaded upwardly in order to bring their cut out portions 21, 21 into alignment with the edges of the bolt i6, and thus permit the bolt 16 to slide freely through the cut out portions toward the left and thus be disengaged from the under side of the rim 38. It would, of course, be possible to have the combination equal to a certain number of turns from the end of the lock screws which bear the nuts 2i, 2| and 23, 23, but this involves the step of threading the screws 22 and 24 all the wa up until they abut against the under side of the plate l2 of lock I0, and then threading them back down again the given number of turns. The operator preferably has a so-called speed wrench which has a socket on its lower end, the inside dimensions and form of which socket conform to the shape of the heads 25, 25 of the screws 22 and 24. The wrench may be made long enough so that the operator may loosen the screws from a standing position. The socket of this speed wrench fits down into the holes 35, in the cover plate 33 and over the heads 25, 25 of the two screws. mensions and form is demanded. Each screw is threaded upwardly a proper number of turns. This results in the removal of the threaded portion of the screws 22 and 24 from the arcuate notches 38, 35 of the bolt l6 (Figure 4) and the :1.

substitution therefor of the cut out portions of the shank of the screws. A rod or pointed instrument is then inserted through the slot 39 in the cover plate 33 and further inserted into the slot I8 of the handle or lug I! of the latch Hi. this rod or pointed instrument, which may be the other end of the speed wrench, the bolt is pried or pushed to the left until the lug or handle I1 abuts against the spacer element l4 of the look. A hook of suitable form is then inserted through the slot 39 of the cover plate 33, and'the cover plate is pulled upwardly above the level of the seat 31 and then slid to the right to disengage the hook 40. The whole cover plate may then be removed from the seat.

To look the cover in place again the reverse order of the above mentioned steps is taken, namely, the cover plate 33 is lowered and the hook 40 is slid under the rim 38 of the seat 31, the right hand edge of the cover plate is then lowered onto the rim 38, a rod or pointed tool is then inserted through the slot 39 and into the slot or notch IB of the lug IT on the bolt, the bolt I6 is pushed or pried to the right, and the screws 22 and 24 are then screwed downwardly tightly against the top surface of the plate H of the lock I0.

As was mentioned above, it is desirable to start the threads of the tapped holes for screws 22 and 24 through the lock mechanism at the same position for each look. It permits the combination to be the same for all looks. This is optional. As will be noted in Figures 1 and 2, the flat edges of the truncated heads 25 of each of the screws face each other when the screws have been drawn upwardly to unlocking position. This is purposely arranged to make the unlocking of the lock easier for the operator who has the proper combination. Should it prove desirable to change the combination of any lock which is in use or of any newly Thus a wrench of prescribed di- 5.

With

constructed lock, it is only necessary to put a small collar underneath the flange 25 of the screws 22 or 24, or to switch the screws in position. The use of a small collar beneath the flange 26 of either or both of the screws 22 and 24 will not result in the head 25 of either of the screws being raised above the surface of the cover plate 33. It will merely mean that when the screws 22 or 24, or bothdepending upon where the newly placed collar is located-is threaded down tightly in position it will not need so many turns downwardly as previously. Consequently, the combination previously used, which consisted of a certain number of turns of the screw upwardly, will now fail to unlock the locking mechanism, for the cut-out portion 21 will not now coincide with the edges of the latch I6.

There is no lock known which cannot eventually be picked-i if enough time is permitted. This locking mechanism is no exception to that rule. However, the length of time necessary to solve the combination is so great that no intruder could safely stay long enough to open the look without being observed. The bolt I5 is flat and wide and so the lock screws 22 and 24 are separated sufficiently far that they cannot be tampered with, damaged or broken together but need to be assaulted separately by anyone attempting to break the lock.

Figures 7 and 8 illustrate another manner of looking a cover plate in position on its seat. In this case the bolt I5 of the lock 10 does not directly engage the under surface of the rim 38 of .the seat 31. Instead, the bolt It operates upon a pivoted latch member 42 which engages the under surface of said rim. The bolt I6 is used to keep the pivoted latching member 42 in engagement with the rim 38 of the seat 3! when the cover plate 33 is in locked position. This pivoted latching means consists of a support 43 afiixed to the under side of the cover plate 33 and a lever 45 pivoted thereto. The outer arm of lever 45 has a hook for engaging a lip 45 on the under side of the rim 38. The right hand arm of pivoted lever 45 is illustrated as abutting against the under side of the bolt l5 of the lock 10. When the locking mechanism 10 is unlocked and the bolt 16 retracted from its present position, the right hand arm of the pivot lever 45 may be moved upwardly toward the under surface of the cover plate 33, which movement will disengage the hooked end of the pivot arm from the lip 46 on the edge of the rim 38 of the seat 31. In order to move the lever 45, a hole 41 is provided in the cover plate 33 through which a hooked instrument may be inserted to pull or pry the right hand arm of the lever upwardly. The greater weight of the right hand arm of the lever 45 causes its hooked end normally to engage the rim 38 because the right hand arm, due to gravity, tends to rotate in a clockwise direction. To lock this lever 45 in this position, bolt I6 may be moved across and above said right hand arm and the screws of the lock then threaded down so that the bolt I6 is immovable and consequently the lever 45 is prevented from being moved.

Notable advantages of my locking means are the following: the lock works satisfactorily under all conditions of weather and climate; it has I sufficient ruggedness and strength to withstand much physical mistreatment; it lies beneath the cover plate and therefore leaves a perfectly flat surface on the top of said cover plate; and it needs to be lubricated only occasionally with graphite and oil. Inaddition 'tothis, it requires no "special shape or-conformation of cover plate and'isadaptable to old-as well as new cover plates for manholes, vault covers, doors, etc.

The configuration of the heads of the bolts and the corresponding shape of the socket wrench may be varied. In fact many of the specific details are optionally variable within the skill of the art.

While I have illustrated and described specific devices, these are not to be considered limiting, for many changes and. modifications may be made without departing from the scope of my invention as defined below.

I claim:

1. The combination with a closure element of a lock comprising a casing, fastening means for securing said casing to said closure element and accessible only from the inside of said closure element, a passageway of substantially rectangular cross section through said casing, a bolt sliding within said passageway, there being a plura'lity of threaded holes through said casing, the bore 'of each of said threaded holes passing partially through the edges of said passageway, arcuate notches in the edges of said bolt which notches complement the bores of said threaded holes when said bolt is positioned for being looked, a plurality of threaded locking screws having heads, said closure element having openings receiving said heads whereby the latter may be positioned to lie within the exterior surface of said closure element, said screws fitting into said threaded holes and being adapted to engage the arcuate notches of said bolt when said bolt is in position for being looked, a cut out portion on the side of each screw shank which cut out portions complement the rectangular passageway when said screws are threaded into unlocking position and thus permit the bolt to slide freely through said passageway, said out out portions being spaced in the shanks of said screws relative to the heads thereof so that when the latter are disposed in said openings said screws are positioned for engaging the arcuate notches of said bolt, an operating lug on said bolt, and a hole in said closure element above said lug to provide access to said bolt.

2. In combination, a 'closure plate, locking means secured to the inside surface of said closure plate, said locking means comprising a'cas ing, a bolt slidably mounted in a passageway in.

said casing, a screw extending through said closure plate and said casing with a portion of the Width of the screw intersecting a portion of the'width of said passageway, said screw and said bolt each having a cutout portion whereby said screw is adapted to be positioned to align the cutout portion thereof with said passageway so that said bolt is slidable therein, or for dis.

posing a portion'of the screw in the cut out portion of the bolt to prevent sliding movement thereof, selectively, the cut out portion of said bolt being disposed so that when said screw is positioned therein a portion of said bolt extends beyond an edge of said cover plate, and said closure plate having an opening therein providing for access only to said bolt.

3. The combination of claim 2 wherein the casing comprises spaced plate members disposed substantially parallel with said closure plate, and said bolt comprises a lug extending laterally of --said spaced plate members in substantial alignment with theopening in said closure plate.

4. In combination, a closure plate, locking means secured to the inside surface of said closure plate, said locking means comprising a casing, a bolt slidably mounted in a passageway,

in said casing, a screw extending through said closure plate and said casing with a portion 'of the Width of the screw intersecting a portion ofthe width of said passageway, said screw and said-bolt each having a cutout portion whereby said screw is adapted to be positioned to align the cutout portion thereof with said passageway so that said bolt is slidable therein, or for disposing a portion of the screw in the cutout por*- tion of the bolt to prevent sliding movement thereof, selectively, the cutout portion of said bolt being disposed so that when said screw is positioned therein said bolt is disposed in a predetermined position with respect to said cover plate, and said closure plate having an opening therein providing for access only to said bolt.

IRWIN H. WITT. 

